Various types of batteries have been developed heretofore, and in every battery, a packaging material is an essential member for sealing battery elements such as an electrode and an electrolyte. Metallic packaging materials have often been used heretofore as battery packaging materials, but in recent years, batteries have been required to be diversified in shape and to be thinned and lightened with improvement of performance of electric cars, hybrid electric cars, personal computers, cameras, mobile phones and so on. However, metallic battery packaging materials that have often been heretofore used have the disadvantage that it is difficult to keep up with diversification in shape, and there is a limit on weight reduction.
Thus, in recent years, a film-shaped laminate including a base material layer, an adhesive layer, a barrier layer and a sealant layer laminated in this order has been proposed as a battery packaging material which is easily processed into diverse shapes and which can be thinned and lightened (see, for example, Patent Document 1). The film-shaped battery packaging material is formed in such a manner that a battery element can be sealed by heat-welding the peripheral edge by heat sealing with the sealant layers facing each other.
Meanwhile, in a manufacturing site of batteries, chemicals such as an electrolytic solution, an acid, an alkali and an organic solvent are used, and therefore a film-shaped battery packaging material is required to have chemical resistance so that degradation, degeneration, damage or the like does not occur even if such a chemical adheres to the battery packaging material. It has been previously known that by providing a coating layer on a surface of a base material layer of a film-shaped battery packaging material (surface opposite to an adhesive layer) using a thermosetting resin, chemical resistance can be imparted to the battery packaging material. However, a two-pack type curable resin has been used heretofore for forming a coating layer using a thermosetting resin, and thus it is required to perform aging under a high-temperature condition for several days to several weeks for curing the resin. Therefore, there has been the problem that the lead time is increased, so that product defects occur due to exposure to the high-temperature condition for a long period of time. On the other hand, for suppressing product defects resulting from aging under a high-temperature condition as described above, it is effective to cure the two-pack type curable resin quickly (in a short time) by increasing the curing temperature of the resin. However, in conventional techniques, there is the disadvantage that when the two-pack type curable resin is quickly cured, curing of the thermosetting resin does not sufficiently proceed, and resultantly, sufficient chemical resistance cannot be imparted to the coating layer.
In view of the conventional techniques, it is earnestly desired to develop a technique for forming on a base material layer of a film-shaped battery packaging material a coating layer which can be quickly cured, and has excellent chemical resistance.